st.patrick regional sec
chemistry 11, block a
chemistry 11, block a
Wednesday, January 27, 2010 7:07 PM
More Stoichiometry-Mass to moles
-Volume @ STP(22.4l/mol)
Examples:
Q:When 1.5g of Oxygen reacts with nitrogen monoxide how many moles of nitrogen dioxide are produced?
A:O2+2NO-->2NO2
1.5gx1molO2/32.0gx2molNO2/1molO2=0.094mol of NO2
Q:If 2.0g of O2 reacts with nitrogen monoxide, what volume of nitrogen dioxide is produced at STP?
A:O2+2NO-->2NO2
2.0gx1molO2/32.0gx2molNO2/1molO2x22.4L/1molNO2=2.8L
Q:In the formation of Copper(II)Oxide, 3.5g of Copper react.How many moles of Copper Oxide are produced?
A:2Cu+O2-->2CuO
3.5gx1molCu/63.5gx2molCuO/2molCu=0.055mol CuO
6:02 PM
Stoichimetry-Coefficients in balanced equations represent moles
-they are also conversion factors
Examples:
Q:If a 0.15 mole sample of methance(CH4) reacts with oxygen how many moles of each product are produced?
A:CH4+202-->CO2+2H2O
0.15molCH4x1molCO2/1molCH4=0.15molCO2
0.15molCH4x2molH2O/1molCH4=0.30molH2O
Q:When 2.1x10-3 mole of Aluminum Hydroxide react with Sulphuric Acid how many moles of Aluminum Sulphate are produced?
A:2Al(OH)3+3H2SO4-->6HOH+Al2(SO4)3
2.1x10-3molAl(OH)3x1Al2(SO4)3/2Al(OH)3=1.1x10-3mol
Q:How many moles of Bauxite(Aluminum Oxide)are requried to produce 1.8 mole of pure Aluminum?
A:2Al2O3-->4Al+302
1.8molAlx2molAl2O3/4molAl=0.90mol Al2O3
Converting to mass requries one additional step
Examples:
Q:How many grams of Bauxite are required to produce 3.5 mole of Aluminum?
A:3.5molAlx2Al2O3/4Al=1.75mol of Al2O3
1.75molx102g/1mol=178.5g=1.8x10^2g(S.F.)
Q:How many grams of water are produced if 0.84mol of phosphoric acid is neutralized by Barium hydroxide?
A:2H3PO4+3BaOH2-->6HOH+Ba3(PO4)2
0.84molH3PO4x6molHOH/2H3PO4x18.0g/1mol=45.4g=45g
Sunday, January 17, 2010 11:29 PM
CALORIMETRY-To measure the heat absorbed/ released by water we need to know 3 things:
1.) Temperature Change (c)
2.) Amount of water (g, kg, mL, L)
3.) Specific heat capacity (kJ/ kg c)
Main Formula: triangle H= mCtriangle T
m= mass of water
C= specific heat capacity
T= change in temp.
11:05 PM
HEAT AND ENTHALPY
words of the day:
Exothermic= releasing heat (a+b -> c+d+ heat)
Exothermic= releasing heat (a+b -> c+d+ heat)
Endothermic= absorbing heat (a+b+heat -> c+d)
Enthalpy= stored chemical energy
-A way to remember which is exo/endothermic just think of the heat exiting from the exothermic reaction, and the other one is just opposite...
-Enthalpy has 'h' as its symbol
-Change in enthalpy has 'triangle h' as its symbol
Tuesday, January 12, 2010 10:11 AM
01/08/10 - DAY1A6 Types of Reactions
SYNTHESIS
________ + __________ > ___________
EX: 2Al + 3F2 > 2AlF3
6Ca + p4 > 2Ca3P2
CoCl2 + 6H2O > CoCl2 . 6H2O
DECOMPOSITION
________ > __________ + ___________
EX: 4H3PO4 > 6H2+ P4 + 8O2
2KClO3 > 2KCl + 3O2
2C12H22O11 > 24C + 22H2 + 11O2
SINGLE REPLACEMENT
* compounds must always have a metal + non metal
EX: 3Mg + 2Al(NO3)3 > 2Al + 3Mg(No3)2
2NaI + Br2 > 2NaBr + I2
DOUBLE REPLACEMENT
EX: MgCl2 + K2SO4 > MgSO4 + 2KCl
Mn(ClO)4 + 2 CaCO3 > 2Ca(ClO)2 + Mn (CO3)2
NEUTRALIZATION
* Between Acids + Bases
_________ + ________ > ________ + H2O
EX: H2SO4 + 2KOH > 2HOH + K2SO4
Ba(OH)2 _ 2HCl > 2HOH + BaCl2
COMBUSTION
*Any combustion reaction involves oxygen
EX: Mg + O2 > 2MgO
EX: CH4 + 2O2 > CO2 + HOH
10:02 AM
01/06/10 - DAY 1DBalancing with C, H & O
1) CH4 + 2O2 > CO2 + 2H2O
2) C8H18 + 25/2O2 > 8CO2 + 9H2O
Words for a Balanced Equation
Aluminum Chloride is mixed with potassium carbonate. Aluminum carbonate and potassium chloride are formed. Write a balanced equations.
2AlCl3 + 3K2CO3 > Al2(CO3)3 + 6KCl
Ex: Sodium reacts w/water to produce hydrogen gas + sodium hydroxide
2Na + 2HOH > H2 + 2NaOH
Acids
Hydrochloric Acid - HCl
Nitric Acid - HNO3
Sulphric Acid - H2SO4
Phosphoric Acid -H3PO4
Acetic Acid - CH3COOH